Liquid crystal display devices are typically equipped with liquid crystal cells and polarizing plates. The polarizing plates, typically formed of a protective film and a polarizing film, are produced by dying a polarizing film of polyvinyl alcohol films by use of iodine and stretching the film, then laminating the protective film to the both sides. In liquid crystal display devices of transmission-type, in some cases, the polarizing plates are attached to both sides of liquid crystal cells and also one or more optical compensation films are disposed. Liquid crystal display devices of reflection-type are typically formed from a reflective plate, a liquid crystal cell, one or more of optical compensation films, and a polarizing plate in this order.
The liquid crystal cells are typically formed from liquid crystal molecules, two sheets of substrates to enclose them, and electrode layers to apply a voltage to the liquid crystal molecules. There are many proposals for the liquid crystal cells that can display ON or OFF depending on the difference of orientation conditions of the liquid crystal molecules; examples of the display mode adapted to transmissive and reflective types include TN (Twisted Nematic), IPS (In-Plane Switching), OCB (Optically Compensatory Bend), VA (Vertically Aligned), ECB (Electrically Controlled Birefringence) and FFS (Fringe Field Switching).
The optical compensation films are utilized in various liquid crystal display devices in order to erase image colors or to widen view angles. Stretched birefringent polymer films are conventionally utilized for the optical compensation films. In addition, optical compensation films having an optical compensation layer formed from lower-molecular-weight or higher-molecular-weight liquid crystal molecules on a transparent support are proposed as alternatives of the optical compensation films of the stretched birefringent polymer films. The liquid crystal molecules, by virtue of wide variety of orientation configurations, can achieve optical properties that are impossible for the conventional stretched birefringent polymer films. In addition, combined constructions of protective films and optical compensation films are also proposed by way that a birefringent property is added to a protective film of polarizing plates.
The optical properties of the optical compensation films depend on the optical properties of liquid crystal cells, more specifically, depend on the difference of the display mode described above. The liquid crystal molecules may bring about the production of optical compensation films having various optical properties corresponding to various display modes of liquid crystal cells. The optical compensation films with liquid crystal molecules have been already proposed variously corresponding to display modes. For example, optical compensation films for parallel aligned liquid crystal cells perform to optically compensate the liquid crystal molecules aligned parallel on a surface of substrates as well as to increase view properties of orthogonal transmissivity of polarizing plates (see Patent Literature 1).
As such, the optical compensation films are nowadays an indispensable member for liquid crystal display devices, thus it has become essential to control precisely retardation of the optical compensation films.
Concerning the control of the retardation, for example, an optical compensation film with an optically anisotropic layer is proposed in Patent literature 2, in which the retardation can be easily adjusted through orientation control of liquid crystal compounds. Non-Patent Literature 1 describes that orientation of rod-like liquid crystal compounds on orienting films depends on a magnitude relation of the surface tensions of the orienting films and the liquid crystal compounds. Non-Patent Literature 2 describes that pretilt angle differs depending on carbon chain lengths of the orienting films at the time of orienting rod-like liquid crystal compounds.
However, there appears no description in the Non-Patent Literatures 1 and 2 with respect to the orientation of disc-like liquid crystal compounds described in the Patent Literature 2.
On the other hand, a technique is proposed to control the orientation of the disc-like liquid crystal compounds on the basis of I/O values of the orienting films (see Patent Literature 3); however, there is no disclosure with respect to the relation between the orienting films and liquid crystal compounds or properties of liquid crystal compounds.
Accordingly, such techniques are currently demanded to be developed that can control easily the retardation of optically anisotropic layers by way of defining the relation between the orienting films and liquid crystal compounds or selecting properties of liquid crystal compounds, and can improve contrast and reduce color-shift as a function of view angles through optically compensating liquid crystal cells by use of the optical compensation films.
Furthermore, in relation to the optical compensation films, inexpensive liquid crystal display devices are desired in which the contrast is improved and color-change as a function of view angles is reduced through optically compensating liquid crystal cells and lessening luminescence defects.
Patent Literature 4 proposes a method for producing an optical compensation film that can satisfy desirable optical properties and also attain progress of productivity by use of liquid crystal compounds having a polymerizable group. Patent Literatures 5 and 6 propose methods for producing an optical compensation film using liquid crystal compounds with polymerizable groups other than those of Patent Literature 4.
However, it is believed that these proposals could hardly attain the objects described above, since there is no description of techniques with respect to improvement of storage stability that is an essential or inherent problem in relation to polymerizable liquid crystal compounds.    Patent Literature 1: Japanese Patent (JP-B) No. 3342417    Patent Literature 2: Japanese Patent Application Laid-Open (JP-A) No. 08-50206    Patent Literature 3: JP-A No. 07-333431    Patent Literature 4: JP-B No. 2692035    Patent Literature 5: JP-A No. 2005-122155    Patent Literature 6: JP-A No. 2005-122156    Non-Patent Literature 1: J. Applied Physics (1976) 47, p. 1270    Non-Patent Literature 2: Synthetic Metals (2001) 117, p. 267